Structural, Magnetic and Magneto-caloric studies of Ni50Mn30Sn20Shape Memory Alloy

TL;DR

This study synthesizes Ni50Mn30Sn20 alloy, revealing its structural, magnetic, and magneto-caloric properties, including phase transitions, magnetic behavior, and potential for magnetic refrigeration applications.

Contribution

It provides detailed characterization of Ni50Mn30Sn20 alloy's phase transitions, magnetic properties, and magneto-caloric effects, highlighting its potential in magnetic cooling technologies.

Findings

Identified austenite to martensitic transition at 127 K.

Confirmed ferromagnetic transition at 222 K.

Measured significant magneto-caloric effects with entropy change up to 3.9 J/Kg.K.

Abstract

We have synthesized a nominal composition of Ni50Mn30Sn20 alloy using arc melting technique. Rietveld refinement confirms the austenite L21 structure in Fm-3m space group. Electrical resistivity has been found to clearly exhibiting two different phenomena viz. a magnetic transition from paramagnetic to ferromagnetic and a structural transition from austenite to martensitic phase. Thermo-magnetization measurements M(T) confirms ferromagnetic transition temperature TC at 222 K and martensitic transition starting at 127 K(MS). Magnetization measurement M(H) at 10 K confirms the ferromagnetic state. Frequency dependence of ac susceptibility \c{hi}' at low temperature suggests spin glass behavior in the system. The isothermal magnetic entropy change values have been found to be 1.14 J/Kg.K, 2.69 J/Kg.K and 3.9 J/Kg.K, with refrigeration capacities of 19.6 J/kg, 37.8 J/kg and 54.6 J/kg for the field change of 1, 2 and 3 Tesla respectively at 227 K.